Kingdom Hearts: Darkness Within
by Leviculus
Summary: Sora's gone missing and now Riku has to search the worlds and fight off the Heartless and the Nobodies in order to save him. While searching for his childhood friend, he struggles with the darkness slumbering inside him.
1. Chapter 1

"I'll race you back! This time I won't lose!"

"That's what you think! Last one there has to swim back!"

"Riku thats cheating!"

"You asked for it Sora, ready...GO!"

The two boys laughed as they ran down the beach. The sounds of waves crashing and the scent of the ocean air was about them. The older boy, Riku, ran ahead of his friend with ease. The gentle breeze blew through his short silver hair. He looked back and saw Sora chasing him. He started to laugh as he turned to face forward. His foot hit a shell, causing him to slip and fall on his butt.

"Ouch!", he screamed as he cupped his butt. Sora ran by Riku stiffling laughter.

"You're gonna swim back Riku!", Sora called back as he leapt over a fallen palm tree and kept going.

"In your dreams Sora!", Riku responded as he got started to get up and took off running again. Sora started to disappear from Riku's sight. "He's gotten faster", Rikue said with a chuckle as he started running faster. He started to round the beach when something caught his eye. He slowed down and looked over his shoulder, and caught a climpse of something dark by the waterfall. "What was... Must have just been my mind playing tricks on me.", he muttered as he sped back up to catch Sora.

Sora looked over his shoulder and saw Riku catching up quickly. He started to run as fast as he could, the docks were only a couple yards away. He checked back one more time as he neared the finish line when his foot caught a shell and caused him to fall face first in the sand. Riku walked up to Sora, his face starting to turn red from trying not to laugh. Sora got up and looked at Riku when he felt somethin poking his head.

"R-Riku...what's on me?", Sora asked nervously. Riku checked Sora's hair and started laughing. "What is it Riku? Tell me!", he begged.

"You got a hermit crab attempting to make a home of you hair up there.", he said as he stepped onto the docks. "Oh and by the way Sora, your swimming home"

"Riku! Get it out!", Sora shouted as he ran up onto the docks. He kept running towards the boat, hands on his head trying to knock the crab off.

"Sora watch-", Riku started as Sora ran off the docks into the cold ocean water.

"RIKU!", cried Sora. Riku walked to the edge and watched as Sora splashed about. "Help me!"

"Nope. You have to swim back remember?", teased Riku as he climbed into the boat.

"Riku!"

* * *

"Riku! Come on get up! Riku!"

Riku opened his eyes and saw Sora with a bucket of water.

"Sora, what's th-", Sora threw the bucket of water on Riku and stuck his tongue out. Riku jumped up and held his arms out, his shoulder length silver hair sticking to his face from the salty water. "You little punk! I'm gonna get you!"

"Gonna have to catch me first!", Sora said and he took off running to the beach. Sora continued to laugh as he ran down the beach. Riku chased after him and his eye caught something by the waterfall. He stopped and looked over, seeing a brief orb of darkness by the waterfall before it quickly disappeared.

"Just like when I was a child...", he muttered as he turned to chase after Sora. When Sora got in his sights he chuckled and started to run faster. He was about to pass Sora and realized he was frozen in midrun. "Sora?" He walked back by him and waved his hand in front of his eyes. "S-Sora?" He looked out to the ocean and saw waves frozen in time.

"What's going on?", he whispered. The was no sound of seagulls cawing or waves crashing. No humid breeze blowing through his hair, no salty taste on his tongue, nothing. He looked behind him at his frozen friend and sighed. "What do I do..?"

Riku stared out at the waves when a voice broke his concentration.

"Riku.."

He turned to see where the voice came from and saw a figure in a dark black cloak headed towards the waterfall. Just the sight of the cloak gave him chills.

"Who are you?", he called. The figure ignored him and continued to walk, slowly disappearing from Riku's sight. Riku cursed under his breath and looked back to his friend once more. "I'll be back to save you Sora."

He started to make his way to the waterfall and stopped just as he rounded the beach. He picked up a decent sized branch and walked along the rocky edge.

"Where are you?", he yelled. He continued to move closer to the waterfall, keeping a decent distance. "I'll ask again, where are you?"

"Riku..."

The voice came from behind him. He turned quickly and saw the rocky wall. He slowly turned around and saw the figure go into the cave by the waterfall.

"Hey! Wait!" He followed the figure into the cave and looked around. All he saw was the drawings him and Sora had done as kids and the weird doorlike structure that was always there. He turned to leave and saw the the exit was gone.

"Are you in here?", he asked quietly, his fear starting to set in. What was happening? Why was Sora frozen? Who is the figure? And why...why is there a light surrounding the structure? He stepped to the door and heard the voice again.

"The answer to your questions lay beyond the door. Use the Key."

"The Key?" He looked around for a key of any sort, but found nothing behind the rocks. All he saw was the drawings, and the door. He threw the branch at the door and sat down.

"Use the Key, Riku."

"What key?", he yelled, hoping for an answer.

"Use the Key."

"Use the Key."

"Use the Key."

The voice continued to repeat itself to Riku. Over and over. Riku held his hands over his ears and closed his eyes. The voice kept at it, continuously repeating itself. Riku stood up and held out his hands.

"Just shut up! Shut up!", he screamed, his anger building. A bright flash of light appeared in his hand. After the light diminished, it was replaced by black handle surrounded by a wide rectangular golden frame. Hanging off the bottom of the frame was a silver chain. Extending from the frame was a long silver...key? Riku held up the strange weapon. "Is that...a key?"

"Use the Key.", came the voice once more.


	2. Chapter 2

Riku looked over the key he held. "This must be the Key the voice was telling me to use." As if the words were some code, the Key began to tug towards the structure. Riku extended his arm and pointed the Key out. A tiny orb of light circled the end then disappeared, being replaced by a beam shooting out of the Key into the door. The light faded, plunging Riku into the darkness.

"Well that helped..", he grumbled to himself.

"Riku! Help!", came Sora's voice from outside.

"Sora!" Riku fumbled in the darkness for a wall. The moment he felt the cool stone on his fingertips, he began to slowly search along it for the exit.

"Riku!", came Sora's voice again, this time more frantic.

Riku started to move along the wall faster. His hand hit empty air, causing him to stumble. He continued to feel his way along the wall until he saw a brief flash of light a couple feet in front of him. He ran out of the cave to see darkness coating the island. Lightning flashed wildly across the sky, hard winds blew against the trees. Dark clouds swirled over his head as he searched.

"Sora, where are you?", he called out again. The high winds whipped his silver hair about his face as he ran against them towards the beach. Large, dark waves crashed against the shore, and thunder cracked, momentarily lighting the night.

Sora turned his head and saw Riku running towards him. Dark forms were beginning to crawl out of the ground. They surrounded the two, their dark heads looking around, small arms twitching to attack. Beady, yellow eyes watched unblinkingly.

"What are these things Sora?"

"I'm not sure, they just started to form a few seconds ago. What happened to the islands? And where'd you go?"

"Sora, I'm not entirely sure what's going on here to be honest." The forms began to creep closer, in on them.

"What do we do Riku?"

"Let me think Sora. I don't know!" Riku looked around for anything to fight with.

"Use the Key."

"The Key..", he whispered. "But how..?" Sora started to back up beside him, the forms having moved up right next to him. One of the forms started to twitch more violently before it leapt at Sora. "Sora look out!" Riku pulled Sora behind him with his left hand, and held out his right hand to stop the form. Riku peeked over his shoulder and saw in his hand the Key again. The form had disappeared. Before he had time to register what just happened the other forms began to attack them. Riku swung the Key at the neareast form, causing it to disappear in a smokey darkness. A solitary heart floated up into the sky and faded away.

Without thinking, Riku continued to swing the Key. Taking out more forms. Releasing more hearts into the dark sky. Sora watched with wide eyes and his friend defeated form after form, wielding the strange weapon so naturally. The final form leapt at Riku, only to be blocked by the Key. Riku quickly followed up with a quick slash, releasing yet another heart. The weapon disappeared as Riku turned to face Sora.

"What was that?"

"I'm not sure yet, but we have time to figure out later. We have to get out of here Sora." As if to add onto the urgency in Riku's voice, the swirling clouds above began to unfold, revealing a giant orb of darkness.

"R-Riku...What is that?"

"Our world is getting swallowed by darkness...", Riku replied, not entirely sure how he knew the answer. "We have to go. Now."

"Where are we going to go? You just said darkness is swallowing our world!"

"Just follow me."

Riku began to pull Sora back to the cave, something in the back of his mind saying that's their way out. A dim light radiated from the back of the cave as they ran towards the entrance. The door emitted bright light from the edges, a single keyhole was fitted directly in the middle. Riku pointed his hand to the door, hoping his idea would work. The sounds of the dying world outside drifted into the cave. Sora grabbed Riku and shook him.

"What are you doing? We need to get out of here!"

"Just wait Sora!" He pushed Sora away and closed his eyes. He continued to hold out his hand and focused, willing the Key to appear. Suddenly the island began to shake, causing Riku to break his concentration.

"Stay here Sora. If that door opens, go through it. I'll catch up." Sora nodded and sat by a larger boulder. "Don't worry about me. Remember what I told you." With that Riku ran out of the cave back out into the dangerous night.

Riku ran to the shore, looking for any more forms. He made his way to the small beach shack and climbed onto the ledge. The bridge connecting the island to a smaller island off the shore was starting to break, planks whipping free and being sucked up into the darkness. The figure he had seen slipping into the cave earlier stood in the middle of the island, looking out across the ocean.

Determined to get answers this time, Riku quickly ran across the bridge. He stopped a few feet behind the figure, unsure of what to ask first.

"Isn't this just beautiful Riku? The darkness...look what it can do. Look at how powerful it is. Just as how they say even in the deepest darkness, there's a shimmer of light to guide you, even in the brightest light exists some amount of darkness."

"Who are you?"

"Why do you fight the darkness in you heart? Can't you feel it inside of you? Can't you feel it looking to be set free? It's who you are, who you're destined to be."

"Shut up and answer my question!"

"Oh, cocky now that the Keyblade has chosen us are we? Do you really believe you can beat me? So be it." The figure hunched over, darkness beginning to swirl around him. Riku stepped back, watching as more and more darkness appeared before him. He couldn't really defeat this guy.. Could he? He thought of Sora hiding in the cave, waiting for him to come back. He had to win. He clenched his fists in determination and watched the figure, waiting for his chance to strike. The Key, or the figure had called it a keyblade, had to appear.

The darkness around the figure subsided as it stood up straight. It took a towards Riku, letting free and invisible force that sent Riku back.

"What was that?", Riku said, mostly to himself.

"That, my dear Riku, was the darkness I mentioned moments ago. Still think you can beat me?", the figure said coldly. He trembled slightly at the figure's power. The figure started laughing, "I see your scared. You should be." With those simple words, the figure's shadow began to stretch out from him. It rose from the ground like the forms before, but something was different about this one. It seemed more menacing. More intent to kill. The shadow's form began to look slightly ghoul-like. It's demonic figure floated close to the figure, dark horns protruding from its head. Riku stared at the newcomer in fear and awe.

"It's so powerful..", he managed to choke out. Riku was becoming more and more conviced he wouldn't be able to win. His body trembled with fear as the malevolent shadow swayed back and forth slowly, crimson eyes focused on Riku.

"Already backing down before the fight even begins? I must say I'm disappointed. I had such high hopes for you too."

"No! I'm not backing down. I'm not afraid of you.", Riku responded quickly, fear layered deeply in his voice.

"Your body language and your own voice give you away." Riku winced slightly.

"Well my actions will prove you wrong."

"Try me.", the figure said coolly, unaffected by Riku's ploy.

Riku looked down at his hand and focused. He once again willed the keyblade to appear, to help him defeat this enemy.

"Any day now would be nice Riku, or can you not summon it? Maybe your little friend Sora would pose a larger challenge than you. He looks like he'd be fun to defeat."

"Shut up!", Riku roared as he charged towards the figure. He reared back his fist to punch it, when the shadow moved in front of it. The shadow moved it's hand forward to stop Riku, when he dropped to his side and slid under it. Once Riku had cleared the shadow, he pushed on the ground to redirect the momentum to regain his footing. The figure watched as Riku's fist came flying towards it's face, unfazed by the threat Riku posed. Seconds before his fist connected with the figure's face, Riku moved his hand and opened his fist, grabbing it's shoulder and pulling it behind him. He turned his body and pulled the figure's back against his chest, and his arm over it's throat. The shadow turned and thrusts it's hand forward, claws pointed out.

Riku's eyes widened as the shadow attacked. He pushed the figure forward some, then kicked of it's back, narrowly avoiding the claws. The figure caught it's balance and turned to face Riku.

"Interesting. You attempted to use me as a shield. Your movement was more precise. Tell me, what fueled you? The urge to protect your friend, or the urge to defeat me?"

Riku looked down and sighed. What had fueled him..? He had threatened Sora. But he also had called Riku weak. Which had struck a nerve more? Riku's body began to shake, slowly at first, then more violently. He looked up, his silver hair hiding most of his face. A smile crept across his face, a dark aura slowly engulfing his body.


	3. Chapter 3

Riku's body rocked with laughter as the darkness surrounded him.

"Lets see how you fair against me this time..", he said before dashing forward. The shadow moved in front of the figure, arms outstretched to catch Riku. Riku leapt into the air, placing his hand on the shadow's shoulder, and bringing his knee up into it's jaw. The shadow's head bent back with a sickening crack as his knee connected. Riku flipped his body over the shadow and kicked off it's back, sending himself towards the figure.

"So you let the darkness take control? Perfect.", chuckled the figure as he sidestepped Riku's fist. Riku landed and turned to look at the figure, the darkness around him rising higher into the air. He clenched his fists tighter and ran to the figure again. "So predictable, learn to fight!", shouted the figure as he caught Riku's fist and slammed it's own fist into Riku's gut. Riku's eyes widened as he coughed and got a slight taste of blood.

The figure pulled Riku close, then kicked him in the chest, sending him into a nearby tree. Riku cried out in pain as he felt the hard bark crash against his spine. He sunk to the ground, the darkness beginning to recede.

"That was pathetic Riku. Where's the anger? You have to weild the darkness, not let it control your every move."

Riku stood up, the darkness around him beginning to dance high into the dying sky. He extended his arm out, a flash of light appearing then dimming to reveal the keyblade. Crouching slightly, he pulled the keyblade back. "You want anger? You got it."

The figure smiled under the hood, awaiting Riku's next move. Riku began to run towards him again. "You just don't learn huh?"

Riku quickly leapt backwards, sending the keyblade flying at the figure in a rapid spin. He placed his feet on the trunk of split palm tree, letting his legs absorb the momentum before he redirected it and kicked off towards the figure, darkness trailing behind him. The figure prepared to jump over the keyblade when it disappeared in a flash of light and reappeared in Riku's hand. He spun in the air, swinging the side of the weapon at the figure's hooded head.

Suddenly the shadow's hand took the blow, then reached up and pulled its head forward to look at Riku. Cursing under his breath, Riku rotated his body and pulled his legs up onto the shadow's chest. He then kicked off it, sending himself higher up. He pulled the keyblade back once more and sent it flying forward at the shadow. The blade pierced the shadow's chest, followed by Riku coming down onto the handle, driving it further into the creature. He quickly dropped to his shoulder and rolled out of the figure's range, a smile still plastered on his face, darkness dancing madly around him.

The figure let free a short chuckle as he dismissed the fallen shadow. "That's better Riku, let your emotions free. Doesn't the darkness feel great?"

"You're going to answer my questions now. Who are you?"

"Oh I'm feeling a bit of hostility to me. Fine, you want to know who I am? Have it your way.", the figure said as it reached to pull down it's hood. Dark brown hair framed his face, spiking out in each direction. The darkness around Riku diminished almost instantly, the face under the hood belonging to his friend Sora.

"Don't lie to me! You're not Sora!"

"Oh I'm not? Then who am I, enlighten me Riku."

Riku looked away, towards the cave where his friend was waiting. Sora had to still be in there. This guy can't be him. More darkness exploded from Riku.

"I told you not to lie! You're not Sora!", Riku screamed once more, keyblade appearing in his hand.

"I may not be Sora, but then again I could be. Are you willing to risk killing your own best friend to find out the truth?" Riku tightened his grip on the keyblade's handle as more rage filled him.

"You tell me, 'Sora', am I?", Riku said as he pointed the keyblade at the imposter, darkness beginning to gather at the end of the keyblade. Riku quickly fired off two large orbs of darkness, followed by him charging to attack the false Sora. The two orbs hit the imposter in a large explosion of darkness. Riku jumped in to strike the finishing blow, but was swiftly sent flying from the cloud of darkness caused by the explosion.

The darkness cleared, the imposter's appearance having changed again.

His skin was now lightly tanned, his face now appearing older. Sora's short, spiky brown hair replaced by long, silver hair. He hovered a few inches above the ground, the dark cloak seeming tighter due to the man's body build.

"That attack might have worked, if your opponent wasn't me. Riku, look around. What do you see?"

"A dying world.."

"And what is causing the death of this world?"

"The darkness."

"Exactly. Now listen carefully, because I hate repeating myself. What do you think brought the darkness to this world?"

"You?"

"Wrong. You let the darkness in."

"What? How?"

"When you unlocked the door. It allowed the darkness to attack this world. Your responsible for the death of the islands, the people on this world, and even possibly your friend hiding in the cave."

"Your kidding me. I caused all of this?"

"That appears to be the case. Don't worry. They didn't really matter anyway Riku. You also unlocked your heart at that same moment in time. You awoke your inner darkness. Look at yourself now. You handle it so naturally." The darkness that had exploded out of Riku faded away. He tossed the keyblade aside and walked towards the man. He stopped in front of him and looked down.

"Is it really my fault?"

"Sad to say, but yes it is."

"You...have to be lying!" Riku punched the man's face, then grabbed him by the shoulders and began to slam his knee into the man's gut repeatedly. Riku rose his knee to hit the man again, but was sent back by an invisible force.

"Ok, you want to play like that Riku? Fine." He snapped his fingers. Riku looked around, expecting the shadow to appear again. Suddenly a scream that was quickly cut off came from within the cave.

"Sora!", Riku called and began running towards the cave to protect his friend.

"It's too late Riku. My Heartless have already taken him captive."

"Your Heartless?"

"Those forms you faught earlier. They captured your little friend. You want him back, learn to fight properly. Might not be a bad idea to learn how to wield that darkness you unleashed. Next time we meet, I won't take it easy on you."

The man chuckled cruelly as he opened a portal made of darkness and disappeared in it, leaving Riku alone on the world that was soon to be nothing more than a memory.

"This is all my fault...", Riku muttered solemnly as he ran to the cave, hoping the door had finally opened.


	4. Chapter 4

Riku ran into the cave, a bright white light had now replaced the doorway. He took a deep breath before running into it. He felt himself falling, yet he also seemed to be staying in place. Everything around him was white. The were no walls, no floors, just an empty plane. He tried taking a step forward, but was overcome by a wave of vertigo. He stumbled and fell to his hands and knees, breathing heavily.

"Welcome Riku.", came a voice from behind him. It sounded kind, yet cruel. Calm, but also filled with rage. He slowly turn to face whoever was behind him, and what met his eyes suprised him.

"Sora..? What happened to you...?"

His once spikey, brown hair that had pointed out in every direction was now a black and white, as if the two colors were clashing perfectly in the middle of his head for dominance. The white side seeming more light and uplifting, the black seemed to radiate an ominous power. The colors of his clothes now reflected the exact same image, a balanced battle between black and white being fought, the darker side radiating the same ominous power as his hair. . The battle waged on even in his eyes, black and white clashing around his pupils. In some places either of the colors would cross over and fade into the opposing color the further in it crossed.

"Sora, what's going on here?"

He just stood there relaxed, but something about him seemed tensed to attack. Riku took a step towards him, a split second before his foot hit the ground his friend had disappeared. He quickly turned around, seeing his friend looking at him with what felt like a sicking mix of compassion and malice. Sora tilted his head to the side, a blank and somehow focused look in his eyes.

"Who are you..?"

He tilted his head to the other side before speaking, "You seek truth and guidance, correct?" The voice held a hint of Sora's voice.

"Yes, where am I?"

"Nowhere, yet then again, everywhere."

"Exactly what does that mean?"

"Your body hosts an incredible amount af darkness. Did you unlock your heart to it?" Riku looked away and hesitated.

"Yes..I did."

"And now you're world has been consumed. Such a shame really."

"Who are you and why do you look like my friend?"

"You might not have trusted me if I didn't take this form."

"Form? What is going on here?"

"You're in my domain."

"You still haven't told me who you are.", replied Riku, becoming irritated, a hint of darkness surrounding him.

"Don't resort to darkness, but maybe it could help you."

"You're not making any sense at all.."

"I can't reveal too much, just know I'm an ally, but at the same time an enemy. Trust me, or don't. Your choice. The answers you seek will be answered here.", with that 'Sora' opened a dark portal and faded away.

Riku looked at the portal and took a deep breath, unsure of what truths he sought that were about to be revealed to him. He slowly exhaled and stepped through the portalm feeling a jolt of energy as the portal closed around him.

A.N. - Yes it's short... School's been chomping on alot of my time, but Imma try to get more time to write more, sorry again for this piddly excuse of a chapter whoever might be reading this.


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